Collapsible container having reinforced edge portions



H. GREL'LEI A ril 1, 1969 COLLAPSIBLE CONTAINER HAVING REINFORCED EDGE PORTIONS Filed July 12, 1967 INVENTOR.

HORST GRELLE BY United States Patent O 3,435,979 COLLAPSIBLE CONTAINER HAVING REINFORCED EDGE PORTIONS Horst Grelle, Munich, Germany, assignor to Bahre-Metallwerk K.G. Filed July 12, 1967, Ser. No. 652,829 Int. Cl. B65d 9/34, 63/00, 7/42 U.S. Cl. 217-69 4 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Field of the invention The present invention concerns a collapsible shipping container, more particularly a rectangular prism shipping box or crate having Wall sections of relatively thin panels of pressed chipboard, plastics material or the like, which are held together by wires, strips or the like of metal and/ or plastics material and/ or fibres.

Description of the prior art Collapsible containers or boxes are known in the trade by the name folding box. These folding boxes have Wall sections and face sections made of thin chipboard. The wall sections form the body and are bent at right angles at their ends in order to serve as abutment for the face walls of the box by means of edge headings formed thereby.

These known folding boxes, however, do not meet the demands made on such packages with regard to their resistance to deformation and their strength, when they are used in international shipment traffic, especially for shipping fruit and vegetables. Such shipping containers must be as light as possible, so they may only have thin walls. They should also be able to stand up to the conditions laid down by international rules according to which their prescribed strength, both empty and full, must be tested by dropping tests, crushing tests, tests on a vibrating table, and static bending tests of the bottom panel.

The box should also be cheap to produce, since it is intended for use generally only in a one-way traffic.

The object of the invention is to produce an improved folding shipping container of the kind referred to so that it conforms to a maximum degree to the requirementa stated above.

SUMMARY OF THE INVENTION The present invention solves this problem in a simple manner in that the wall sections forming the folding box body have a constantly increasing wall thickness in their face regions adjacent to the edges which are bend at right angles, to twice or three times the central thickness, this taking place over a length between 8 and 30 times the central wall thickness, preferably 20 times. As shown by experiments, this measure increases the strength and rigidity of the box without any noticeable increase of the weight of the box and hence a higher consumption of material to such an extent that it conforms to the international permit requirements with minimum use of material.

The effectiveness of the reinforcement may also be improved by the fact that wires, strips or the like binding the crate body adjacent to the end faces, surround the region of constant increase at a distance from the end walls amounting to about 70 to of the width of this increment region. This results in an improved bracing effect of the body Walls against bending stress, and corresponds substantially to the effect of a bracket in continuous girders.

If the wall sections of the box of the invention are pressed from chipboard, then a further increase in strength may be obtained by more highly compressing the material in the tapered end regions than in the wall section between these reinforced end regions. To obtain the reinforcement it is necessary to charge more material into the pressing mould, at the edges, and it is possible to dimension this additional charge so that the required higher compression of the reinforcing regions occurs.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF PREFERRED EMBODIMENT A crate as shown in FIG. 1 comprises four wall sections I pressed from chipboard forming the box body, and the two end walls 2 also pressed from chipboard which are supported against the edge sides 3 bent at right angles with respect to the ends of the wall sections 1. The box body is bound together by wires 4 which are secured by staples 5 to the wall sections 1, the ends of which, at the crate edge 6, are formed into loops 7 which are used to close the filled box tightly. The end walls 2 are connected by means of wire loops 8 with the upper and lower wall sections 1 ,of the body by inserting them through slots 9 and bending them over. The wall sections 1 of the body and the end Walls 2 may have vent holes 10 formed therein.

As shown in FIGS. 2 and 3, the wall thickness of the wall section 1 is progressively increased in the end face region Z adjacent to the border edge 3. This increase, which also extends into the edge 3, imparts to each wall section 1 substantially the cross-sectional shape of a graduated truss girder and, where it is supported against the end walls 2 and embraces them with its turned over edges 3, it has a wall thickness twice to three times the original wall thickness. This results in an increase in strength and resistance of the box to impact and dropping stresses, without substantially increasing the weight of the box and hence the material consumption. The length of the reinforced tapered face region Z is proportional to the increase in strength required from the increase in wall thickness. This taper may amount to between 8:1 and 30:1. The most advantageous ratio has proved to be 20:1 because the increase in rigidity obtained thereby assumes a favourable relationship with the increased consumption of material necessary for the reinforcing. The tapered increase in wall thickness in the end face region Z of the wall section 1, as shown in FIG. 2, may occur equally from an imaginary medial plane of the wall in two directions. However, as shown in FIG. 3, it may taper only from one of the two cover surfaces. In FIG. 3 this is the outer cover surface. This produces a substantially troughlike shape on each of the outer surfaces of the box body which not only increases the resistance to denting of the wall sections 1, but also increases the ventilation of a stack of crates, because air can penetrate between the bottom and top walls of two crates placed on top of each other.

Finally, it is advantageous, as shown in FIG. 2, if the wires 4 extending in across face regions Z are so arranged that they engage around the region Z of the end Wall 2 at a distance A from their ends which amounts to about 70 to 75% of the width of the tapered region Z. This provides maximum bracing effect of the body walls and counteracts bending stresses caused by the contents of the box.

The invention is not limited to the embodiments as shown in the drawings; thus for example the box body could be hexagonal, octagonal or even polygonal. The wall sections 1 and 2 instead of being made of chipboard could be pressed from suitable plastics material, and in place of round section Wires of metal or plastics material, metal, plastics 0r fibre strip could be provided.

I claim:

1. A collapsible prismatic folding box comprising thin wall sections and end sections of pressed material, with binding members extending round said box near its ends, characterised in that said wall sections have their ends embracing said end sections thickened progressively towards their edges and being one integral thickness, said thickness increase being between 2 and 3 times the centre .4 thickness of said sections, and said edges being turned over at 90.

2. A folding box as recited in claim 1 wherein the thickening of said edges takes place over a length between 8 and 30 times, preferably 20 times, the central thickness of said wall sections.

3. A folding box as recited in claim 1 wherein said binding members are metal Wire's surrounding said box at a distance inwards from said end walls between 70 and 75% of the width of said thickened region.

4. A folding box as recited in claim 1, wherein the material of said wall and end sections is chipboard, said material being more highly compressed in said progressively thickened portions than in said central portions of said wall sections.

References Cited UNITED STATES PATENTS 948,503 2/1910 Ferguson 217--17 XR 2,262,267 11/1941 Boeye. 2,729,386 1/1956 Haddad 2l7-17 XR FOREIGN PATENTS 540,675 10/1941 Great Britain.

H RAPHAEL H. SCHWARTZ, Primary Examiner.

U.S. Cl. X.R. 220-74 

